Protective device for use with enclosed bus bar distribution systems



Jan. 11, 1949. w. H. FRANK 2,458,583

- PROTECTIVE DEVICE FOR USE WITH ENCLOSED BUS BAR DISTRIBUTION SYSTEMS Original Filed Dec. 6, 1943 y 2 Sheets-Sheet 1 IEILJ INVENTOR.

BY I

W. H. FRANK PROTECTIVE DEVICE FOR USE WITH ENCLOSED Jan. 11, 1949.

BUS BAR DISTRIBUTION SYSTEMS Original Filed Dec. 6, 1943 2 Sheets-Sheet 2 j w w PROTECTIVE DEVICE FOR USE WITH ENCLOSED BUS BAR DISTRIBUTION SYSTEMS William H. Frank, Detroit, Mich., assixnor to Bulldo: Electric Products Company, Detroit, Mich.

Continuation of application Serial No. 513,145

December 6, 1943. This application July 1, 1947,

Serial No. 758,251

8 Claims. (Cl. 175-294) This application relates to electrical distribution systems and particularly to protective devices for such system, and is a continuation of my prior application, Serial No. 513,145 of December 2 bus duct exceeds a predetermined amount, I have provided a protective device which I will now describe.

The protective device includes a sheet metal 6, 1943, now abandoned. 5 support or box 20 having an open back, having This application disclosed a device adapted to extended sides 2| formed with flanges 22 which be plugged into any plug-in point of 9, bus d ct, may be attached to the duct flanges by bolts passof the character shown in my Patent No. 2,041,675 n h u h he bolt h les 2 of h x fl n e and having or adapted to be connected to a pro- 22 nd n t flanges it Of the duct, w r y tective element energized and activated, upon a the box may be remevebly mounted on e ductrise in temperature within the bus duct in the The Open back of the 110K 0 is elosed y the et vicinity of the bus bars to an excessive degree, to itselfe Open front o the heli is c s by a provide an alarm, or to open the bus bar circuit, hinge Cove h vi e e D1111 hehdle etc. Extending from side to side of the box he and In such a, system, numerous runs of bus duct 15 suitably mounted on the sides as by means of the extend in mains and branches over a large r brackets 26 is a block 2] of insulation. ll l'ounted of a factory or the like and at closely spaced on that block in a manner to project through points, for example is" apart, there are access open back of the box are three prongs ti openings for plug-in devices of various forms. The prongs 2e are formed with contac 1- The device hereof is one form of pineand it may 26 e 3 nd re p iti ne and f rm d t en a e be plugged into any access point of the system and e meke Co tact with the two outside bu" we as many such devices may be used as are required. and the prongs themselves are formed ith straps In addition, the construction of such system which mount fuse holders within the box, and of the device her-sci such th t, h d these providing connectors and lrlolders for the vices may be used t any desired point i th ferrule ends of a resistor provided with congys'fiegig'g; d vi may b plugged into the system hector tap off lugs which can be selected t; any point Wherever it; seems d i bl m; that a specific portion of the resistor be time to install such a device, the cleterrci. on Resietel Serves e t t being dependent on. the environmental cond, ions Se e5 o p e a s e volt e v 1 of the points of the system as they may change Preteetive meehs 111 from time to time. Such a device is a self=convflltege across the bus s is hi tained protective unit which is mounted on a bus desired for the alarm. duct, measures the temperature within such bus The e Prehge e s Fhetltited duct at the point of a lication, is energized by elects s positioned s as n t to amass the the bus bars of such bus duct and protects such 35 Center bus This p ne is not formed as a bus duct by providing an alarm or by opening the contact prong, but rather is formed a mount circuit of which the bus bars of such circuit form for a thermally ressonsivc r m t sw tch a part. normally open but adapted to close when the tem- For an understanding of the protective device peretfiife u d n the switch exceeds a p elierein disclosed, reference should be had to the so mi d mo n The prone d l w appended drawings. larly the thermally responsive switch thereof is In these drawings, thus located within the duct. when the box fill is Fies. i, 2 and 3 are respectively front, sid a d mounted thereon, in a position intimately asso end Views 0f the pl'gtective device. ciated with the bus bhls 50 as 530 lelSpSYlCi ZDEO= Fig. 4 is a wiring diagram. portionately to the temperatures of the bus bars. Fig. 3 shows, in cross section, an electrical di Que of the elements of the switch is connected tribution system comprising a duct or casing I it y a conductor 3? o One Of the ps 0f formed with flanges H and containing bus bars It. the resistor 33. Another conductor 38, connected At suitable points along the run of the duct lo to the other element of the switch 3%, is connected are prong entrances 0r apertures M in the form to a lamp socket 40 mounted on cover 24 and pro oi. crescent shaped slots whereby each aperture viding aholder nd n t r f lalemp H which straddles the three bus bars 12 and each aperture f s a protective m ns i t e ature of an can be entered into by three prongs of a plug for alarm. The lamp socket is connected to the concontact with the three bus bars. Branch plugs ductor 38 and thus to the switch 36, and through are shown in the aforesaid patent for establish 5 another conductor 43 is connected to one of the ing connection between a three conductor branch holders 32 for the end of the resistor. or load circuit through the plug-in device to the Formed on one end of the box are binding" three bus bars. posts 41 which are connected respectively by con- In order to furnish an alarm or other protecductors 48 to the same portions of the device tive action, in the event the temperature in the 00 to which are connected the terminals of the also to binding posts 5| of the circuit breaker.

This breaker forms another protective means inasmuch as it controls the energy source for the bus bars I2. This circuit breaker 30 may be located at a point remote from the device 20, being connected to the device 20 through the conductors 49.

The circuit breaker 50 may be of any suitable type; it may be a normally closed breaker, ac-- tuated to open automatically upon the closing of the circuit through the conductors 48 and 49. by the closing of the switch 36, and actuated or energized from the bus bars I2 through the contacts 30. For example, the circuit breaker is shown as having a shunt trip coil 52 which, when energized, opens a normally closed latch of the breaker so as to release the contactors f the circuit breaker to open the lines which form the source for the bus bars i2, upon the closing of the branch or shunt circuit from the bus bars l2, through the contacts 30, the fuse holders 32, and the switch 36, through the conductors t8 and Q9.

The action of the device is as follows:

Upon the attainment of an excessive temperature within the duct, the switch 36 closes the control circuit to the lamp ll and to the shunt trip coil 52 of the breaker ill, to produce a protective action, either an alarm by the lighting of the light ll and/or a protective circuit opening by the opening of the breaker B. When the temperature within the duct returns to a safe point or level, the switch 36 opens, once more to open the control circuit which supplies the light tl and the circuit breaker shunt trip coil 52 and these are no longer energized and no longer function to alarm in one case or to open the circuit in the other.

It will be observed that the protective device herein disclosed is a unitary self-contained device which does not require to be wired to the bus duct it is intended to protect, but rather may be plugged into or associated with that bus duct directly at any point thereof in exactly the same way that any branch plug is plugged into the bus duct.

It will also be observed that the device hereof is responsive to the temperature of a feeder system, the bus bars and casing, rather than to the temperature of a branch load device, and is energized by the feeder system to which it responds rather than by any other system and that it protects the feeder system to which it responds and which energizes it.

It will also be observed that the control circuit established in the device and shown as activating the lamp 4| or the trip coil 52 of a circuit breaker may be considered as a control circuit for activating any type of protective device, whether it be a lamp 4| or a trip coil 52 or an audible signal, such as a bell, not shown, or a flag to be moved back and forth, not shown, or any other type of protective action may be obtained.

It will also be observed that though the device is shown as having two activated devices, the lamp 4| and the trip coil 52, that in some instances, binding posts 41 and conductors 48 may be omitted, so that the device has only one acivated device, the lamp 4|. Also, it is possible to omit the lamp socket 40 and the conductors 38-43, retaining connectors 41 and conductors 48, so that only one activated device, the trip coil 52, is retained.

Now having described the protective device herein disclosed, reference should be had to the claims which follow:

Eli)

did

tact fingers in series through said protective I claim:

1. For use with an enclosed bus bar distribution system comprising an enclosing casing surrounding bus bars and having numerous access apertures in the wall thereof at spaced points for receiving plug-in devices, a plug-in device comprising a support, means for removably mounting it on the outside of the casing at an aperture, projecting members mounted on the support and projecting from it so as to be insertabie into the casing through such aperture, certain of the projecting members being formed as contact fingers to engage and make contact with the bus bars in the casing, another of the projecting members being in the form of a thermally responsive switch adapted to respond to the temperature within the casing near the bus bars, an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch.

2. In combination with a bus bar system comprising bus bars and a casing around them, said casing having numerous access openings at spaced points for receiving plug-in devices, a

plug-in device comprising a support removably mounted on the outside of said casing at an opening and having three projecting members mounted thereon and projecting therefrom'into said casing through said opening, two of said projecting members having contact fingers engaging and making contact with said bus bars in the casing, the third projecting member being in the form of a thermally responsive switch, responsive to the temperature within the casing, and an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch.

3. For use with an enclosed bus bar distribution system comprising an enclosing casing surrounding bus bars and having numerous access apertures in the wall thereof at spaced points for receiving plug-in devices, a plug-in device comprising a support, means for removably mounting it on the outside of the casing at an aperture, projecting members mounted on the support and projecting from it so as to be insertable into the casing through such aperture, certain of the projecting members being formed as contact fingers to engage and make contact with the bus bars in the casing, another of the projecting members being in the form of a thermally responsive switch adapted to respond to the temperature within the casing near the bus bars, an electrically energizable protective means, and connections for connecting said conmeans and said switch, whereby such protective means may be energized by said bus bars through said contact fingers-and switch, said protective means being mounted on said support, whereby said support, said projecting members and said protective means together form a unitary self contained assembly.

4. In combination with a bus bar system comprising bus bars and a casing around them, said casing having numerous access openings at spaced points'for receiving plug-in devices, a plug-in device comprising a support removably mounted on the outside of said casing at an opening and having three projecting members mounted thereon and projecting therefrom into said casing through said opening, two of said projecting members having contact fingers engaging and making contact with said bus bars in the casing, the third projecting member being in the form of a thermally responsive switch, responsive to the temperature within the casing,- and an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch, said protective means being mounted on said support, whereby said support, said projecting members, and said protective means together form a unitary self contained assembly.

5. For use with an enclosed bus bar distribution system comprising an enclosing casing surrounding bus bars and having numerous access apertures in the wall thereof at spaced points for receiving plug-in devices, a plug-in device comprising a support, means for removably mounting it on the'outsideof the casing at an aperture, projecting members mounted on the support and projecting from it so as to be insertable into the casing through such aperture. certain of the projecting members being formed as contact fingers to engage and make contact with the bus bars in the casing, another of the projecting members being in the form of a thermally responsive switch adapted to respond to the temperature within the casing near the bus bars, an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch. said protective means being remote i'rom said support but adapted to be electrically connected to 1 through said connections.

6. In combination with a bus bar system comprising bus bars and a casing around them, said casing having numerous access openings at spaced points for receiving plug-in devices, a plug-in device comprising a support removably mounted on the outside of said casing at an opening and having three projecting members mounted thereon and projecting therefrom into said casing through said opening, two oi said projecting members having contact fingers engaging and making contact with said bus bars in the casing, the third projecting member being in the form of a thermally responsive switch, responsive to the temperature within the casing. and an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch, said protective means being remote from said support but adapted to be electrically connected to it through said connections.

7. For use with an enclosed bus bar distribution system comprising an enclosing casing surrounding bus bars and having numerous access apertures in the wall thereof at spaced points for receiving plug-in devices, a plug-in device comprising a support, means for removably mounting it on the outside of the casing at an aperture, projecting members mounted on the support and projecting from it so as to be insertable into the casing through such aperture, certain of the projecting members being formed as contact fingers to engage and make contact with the bus bars in the casing, another of the projecting members being in the form of a thermally responsive switch adapted to respond to the temperature within the casing near the bus bars, an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch so that the'same single distribution system mounts said device, energizes the protective means of said device, supplies the temperature condition to which said device responds, and is the system that is protected by said device.

8. For use with an enclosed bus bar distribution system comprising an enclosing casing surrounding bus bars and having numerous access apertures in the wall thereof at spaced points for receiving plug-in devices, a plug-in device comprising a support, means for removably mounting it on the outside of the casing at an aperture, projecting members mounted on the support and projecting from it so as to be insertable into the casingthrough such aperture, certain of the projecting members being formed as contact fingers to engage and make contact with the bus bars in the casing, another or the projecting members being in the form oi! a thermally responsive switch adapted to respond .to the temperature within the casing near the bus bars, an electrically energizable protective means, and connections for connecting said contact fingers in series through said protective means and said switch, whereby such protective means may be energized by said bus bars through said contact fingers and switch so that the same single distribution system mounts said device, energizes the protective means of said device. supplies the temperature condition to which said device responds, and is the system that is protected by said device.

' WILLIAM H. FRANK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,458,091 Betts May 22, 1923 1,729,581 Vaughan Sept. 24, 1929 1,782,458 Brennen Nov. 25, 1930 2,056,040 Dozier Sept. 29, 1936 2,059,987 Frank et al. Nov. 3, 1936 2,088,105 Frank et al. July 27, 1937 2,328,770 Johnson July 0, 1943 

